Definition of "quadrant"

One of the four sections made by dividing an area with two perpendicular lines.  examples

(mathematics) One of the four regions of the Cartesian plane bounded by the x-axis and y-axis.  examples

(geometry) One fourth of a circle or disc; a sector with an angle of 90°.  examples

(nautical) A measuring device with a graduated arc of 90° used in locating an altitude.  examples

(college basketball) One of the four categories of team wins and losses, as categorized by strength of schedule.  examples

(obsolete) A square or quadrangle.